1. Field of the Invention The present invention relates to a method and apparatus for manufacturing discrete elements and the discrete elements and more particularly to such a method and apparatus which are particularly well suited to the manufacturing of substantially planar discrete elements such as labels and still more particularly labels of the pressure sensitive type in a continuous, rapid operation and having application to the manufacture of labels of a wide variety of different types.
2. Description of the Prior Art
There are a variety of industries in which discrete elements must be manufactured at high rates of speed, but where the cost of such manufacture and the limitations inherent in conventional methods and apparatus severely restrict such manufacture. For example, the label manufacturing industry produces labels which are typically sold in rolls consisting of a carrier or release sheet on which are adhesively, but releasably, arranged a multiplicity of labels. Typically the purchasers of such rolls are manufacturers and/or packagers of products. By way of illustration, bottlers of products such as milk, employ machines which accept such rolls of labels and which automatically and successively dispense labels from the rolls and individually apply the labels to the bottles or containers of milk in a predetermined orientation and location. The labels are, of course, printed to order for the bottler so as to contain information relating to the particular products to which they are to be applied.
Label manufacturers must have the capability of manufacturing labels of a multitude of different types so as to be able to meet the needs of their customers. Thus, label manufacturers may be requested to produce labels of virtually any size and shape, of a variety of different materials, with printing which is exposed or buried beneath a lacquer or transparent plastic film as well as to provide labels having multiple surfaces or portions which can be torn off by the end purchaser for use as a coupon or the like. For example, in the bottling industry, where packaging, distribution and display of the bottles causes the bottles to abrade each other, it is desirable to use labels in which the printing is buried beneath and readable through a protective surface so that such printing is not worn off.
A further complication for label manufacturers resides in the fact that adhesives employed to retain the labels on a carrier sheet and thereafter for retaining the label on the product are often slow to set or cure. Such curing is commonly too slow to permit the label manufacturers to produce their own laminated stock, print, die cut, strip the waste matrix from the carrier sheet and wind the carrier sheet bearing the resulting labels into a roll, all in a single continuous process. For purposes of description herein the terms "prelaminated stock" and "laminated stock" are used to mean a carrier or release sheet to which an element sheet has been adhesively attached, but wherein printing, die cutting and other processing of the element sheet has not been carried out. Thus, "prelaminated stock" and "laminated stock" are used herein to mean adhesively interconnected carrier and element sheets disposed in registry with each other to form a lamination, but not otherwise processed to form labels on the carrier sheet. Such prelaminated stock is most commonly wound into a roll for storage, handling and subsequent processing to form labels.
Prior art efforts to form laminated stock, print, die cut and otherwise complete rolls of labels in a single continuous process have resulted in the adhesives migrating, prior to setting of the adhesive, beyond the peripheries of the labels during manufacture and thereafter. In such prior art efforts the problem of adhesive migration has been chronic. Adhesive migration has interfered with die cutting of the labels and stripping of the waste matrix therefrom as well as with winding of the carrier sheet bearing the labels into a roll. Further, once the carrier sheet bearing the labels is wound into a roll, the adhesive may continue to migrate beyond the peripheries of the labels causing surfaces within the roll to stick together and, at very least, interfering with dispensing of the labels from the carrier sheet. Additionally, it has been found impractical to allow the adhesive to set once the prelaminated stock has been formed and prior to such printing, die cutting, stripping and winding steps since this setting or curing process, depending upon the type of adhesive, often takes seven full days to be completed.
Consequently, conventional practice calls for label manufacturers to buy prelaminated stock, or manufacture it themselves and allow it to cure, in meeting their needs and those of their customers. The preliminated stock is thereafter printed and die cut to form the labels in accordance with the needs of those customers. This requires label manufacturers to maintain large inventories of prelaminated stock of a wide variety of types so as to be able to fill, on relatively short notice, their customer's orders. Not only are such inventories expensive to maintain and store, but the prelaminated stock is itself expensive to purchase.
Still further, because of the foregoing conventional practices, it is, as a practical matter, impossible to manufacture labels of certain types since printing must conventionally be performed by the label manufacturer and prelamination of the stock is performed by another company prior to receipt by the label manufacturer. For example, it is as a practical matter not possible to produce labels in which the printing is captured on the reverse side of a transparent element sheet and thus between that element sheet and its carrier sheet. This is the case because, of course, the printing must be applied to the underside of the transparent element sheet in order to be visible through the element sheet and yet it is the manufacturer of the prelaminated stock, not the label manufacturer, which must adhesively apply the element sheet to the carrier sheet. Referring again to the example of bottling companies, this makes the production of buried print labels, wherein the printing is buried beneath and readable through a transparent film in order to protect the printing from scuffing by other bottles, impractical or inordinantly expensive to produce.
Therefore, it has long been known that it would be desirable to have a method and apparatus for manufacturing discrete elements and the discrete elements, such as labels borne by a carrier sheet, wherein all steps involved in producing such elements can be performed at one place of operation and in a single continuous process permitting label manufacturers to produce labels of virtually any type rapidly, inexpensively and without requiring the purchase and maintaining of an inventory of prelaminated stock.